Refrigerant compressor

ABSTRACT

The invention relates to a refrigerant compressor, comprising: a preferably hermetically sealable compressor housing; an electric drive unit, comprising a rotor ( 4 ) and a stator ( 3 ); a crankshaft ( 1 ), which is connected to the rotor ( 4 ) for conjoint rotation and which has a longitudinal axis ( 2 ); a piston-cylinder unit, which can be driven by the crankshaft ( 1 ); wherein the electric drive unit is designed as an external rotor motor and the rotor ( 4 ) has a carrier element ( 12 ) extending outward radially with respect to the longitudinal axis ( 2 ) at least in some sections and the carrier element ( 12 ) is connected to the crankshaft ( 1 ) for conjoint rotation. According to the invention, in order to enable an increased delivery rate of lubricant from a lubricant sump together with preferably low or reduced height of the compressor, a sleeve-shaped lubricant receiver ( 8 ) for centrifugally conveying lubricant from a lubricant sump formed in a bottom region of the compressor housing toward the piston-cylinder unit is provided on a side of the carrier element ( 12 ) facing away from the piston-cylinder unit ( 5 ), the sleeve-shaped lubricant receiver ( 8 ) being joined to the carrier element ( 12 ) for conjoint rotation.

FIELD OF INVENTION

The invention concerns a refrigerant compressor with a preferablyhermetically sealable compressor housing, an electric drive unitcomprising a rotor and a stator, a crankshaft that is nonrotatablyconnected to the rotor and that has a longitudinal axis, and apiston-cylinder-unit driven by the crankshaft, wherein the electricdrive unit is made as an external rotor motor and the rotor has acarrier element extending radially outward with respect to thelongitudinal axis at least partially, and the carrier element isnonrotatably mounted on the crankshaft.

PRIOR ART

Refrigerant compressors, in particular hermetically encapsulatedrefrigerant compressors, have long been known and are used chiefly incooling appliances such as refrigerators or chilled display cases. Therefrigeration process per se has likewise long been known. A refrigerantis heated in an evaporator by absorption of energy from the space thatis to be cooled and then superheated and, by means of the refrigerantcompressor, pumped to a higher pressure level in a piston-cylinder-unitby a piston moving back and forth in a cylinder housing, where therefrigerant releases heat via a condenser and is transported back to theevaporator via an expansion valve, in which a reduction of pressure andcooling of the refrigerant takes place. The motion of the piston isimplemented via a crank drive comprising a crankshaft that is driven byan electric drive unit.

The electric drive unit made as an external rotor motor comprises astator, which as a rule is made of a bundle of laminations and wirewindings and is situated radially inward with respect to thelongitudinal axis, thus closer to the crankshaft. Moreover, the driveunit comprises a rotor, which is disposed outward with respect to thelongitudinal axis and outwardly surrounds the stator at least partially.A carrier element here serves as a connection between theelectromagnetic components of the rotor, for example permanent magnetsthat are distributed over the circumference and are connected to eachother via a shading ring, and the crank drive, in particular thecrankshaft. The carrier element is connected to the crank drive, inparticular the crankshaft, in a form fit, friction fit or a positivelock fit, in order to drive the crank drive by the electromagneticinteraction between rotor and stator during operation. The carrierelement as a rule is connected to an end section of the driveshaft thatfaces away from the piston-cylinder-unit and extends radially outwardfrom the crankshaft with respect to the longitudinal axis. In otherwords, the carrier element is connected to a free section of thecrankshaft that faces away from the piston-cylinder-unit, while most ofthe crankshaft is mounted in a bearing bushing. In this case, thecarrier element usually grips the stator from below; in other words, thecarrier element is disposed between the side of the stator turned towardthe oil sump and the oil sump.

Usually, the drive unit is made either as an asynchronous motor, whereinthe stator comprises a bundle of laminations and/or copper or aluminumwire windings and the rotor comprises a bundle of laminations andaluminum legs with aluminum shading rings, or is made as a synchronousmotor, wherein the stator comprises a bundle of laminations and/orcopper or aluminum wire windings and the rotor comprises a plurality ofpermanent magnets.

In order to lubricate the piston-cylinder-unit and the crank drive, inparticular the crankshaft, during operation, there is alubricant-conveying system, by means of which lubricant is transportedfrom a lubricant sump building up in a bottom region of the compressorhousing during operation in the direction of the piston-cylinder-unitduring the operation of the refrigerant compressor.

The lubricant-conveying system is generally formed at least in part bythe crankshaft, where the crankshaft has at least one axial drillingand/or one eccentric drilling at the end opposite thepiston-cylinder-unit, preferably on an end face of the crankshaft,through which lubricant is transported in the direction of thepiston-cylinder-unit because of the centrifugal force in the rotation inthe crankshaft. In addition or alternatively thereto, the crankshaftoften has a helical groove made on the circumferential surface in acentral section, which transports the lubricant upward on thecircumferential surface and is connected to the axial drilling and/orthe eccentric drilling.

A disadvantage of the prior art can be seen in that the overalltransport power of the lubricant-conveying system becomes reduced by thelubricant transport height that must be overcome, in particular whenpicking up the lubricant from the lubricant sump. Said reduction of thetransport power results from the amount of lubricant that can betransported by a transport based on centrifugal force, which amountdiminishes with increasing transport height.

AIM OF THE INVENTION

Therefore, it is an aim of the current invention to overcome thedisadvantages of the prior art and to propose a refrigerant compressorwith a drive unit made as an external rotor motor, which enables anincreased power for transport of lubricant from a lubricant pump with apreferably lower, or reduced, height of the compressor.

DESCRIPTION OF THE INVENTION

In order to feed lubricant into a drilling that runs parallel to alongitudinal axis of the crankshaft or at an angle to the longitudinalaxis, preferably an eccentric drilling in the crankshaft disposedeccentrically with respect to the longitudinal axis, without the end ofthe crankshaft opposite the piston-cylinder-unit projecting far abovethe rotor and without the end of the crankshaft opposite thepiston-cylinder-unit dipping into the lubricant sump, a sleeve-shapedlubricant receptacle is connected nonrotatably, not to the crankshaftitself, hut rather to the carrier element. By attaching the lubricantreceptacle to the carrier element, the lubricant receptacle rotatestogether with the crankshaft in the operating state, since the carrierelement is itself connected nonrotatably to the crankshaft.

In the operating state, the sleeve-shaped lubricant receptacle dips intothe oil sump, whereupon lubricant can pass into the lubricantreceptacle, for example, through a lubricant inlet hole. The lubricantreceptacle is usually made of a metallic material or a plastic. Due tothe sleeve shape of the lubricant receptacle, thus the formation of thelubricant receptacle as a hollow body in which the lubricant can beheld, lubricant in the lubricant receptacle is forced by centrifugalforce to the inner wall of the lubricant receptacle, whereupon thepressure rises and the lubricant is transported toward the end of thecrankshaft. Typically a lubricant parabola, or a parabola-shaped columnof lubricant, forms within the lubricant receptacle.

By mounting the lubricant receptacle on the carrier element it is nolonger necessary for the crankshaft to project beyond the carrierelement in order to be able to attach the projecting section of thelubricant receptacle. The lubricant transport height can be reduced bythis step, which leads to an increase of the transport power of thelubricant-conveying system. In other words, the transported amount oflubricant per unit of time is higher with the connection of thelubricant receptacle to the carrier element according to the inventionthan with a traditional connection of the lubricant receptacle to an endof the crankshaft that projects beyond the carrier element.

Through the higher transport power, a sufficient lubrication of thepiston-cylinder-unit can be ensured at lower rotary speeds, so that therefrigerant compressor can be operated in an energy-optimized manner.

Thus, it is provided according to the invention that a sleeve-shapedlubricant receptacle for centrifugal transport of lubricant toward thepiston-cylinder-unit from a lubricant sump formed in a bottom region ofthe compressor housing is provided on a side of the transport elementfacing away from the piston-cylinder-unit, where the sleeve-shapedlubricant receptacle is mounted nonrotatably on the carrier element.

“Nonrotatably connected” should be understood to mean that the lubricantreceptacle rotates together with the crankshaft during the operation ofthe refrigerant compressor, and no relative movement between thelubricant receptacle and crankshaft arises. Said mechanical connectioncan be achieved on the one hand by the lubricant receptacle and carrierelement being separate components and the lubricant receptacle beingattached nonrotatably to the carrier element, thus in a form fit,friction fit, or positive lock fit. On the other hand, the nonrotatablyconnection can also be achieved if the carrier element and lubricantreceptacle are made in one piece.

In one embodiment of the invention, it is provided that the carrierelement has a central through-opening running coaxially to thelongitudinal axis, wherein the sleeve-shaped lubricant receptacle is aseparate component and a fastening portion of the sleeve-shapedlubricant receptacle is mounted on the carrier element in the region ofthe through-opening. Since the lubricant receptacle and carrier elementare separate components, the sleeve-shaped lubricant receptacle as arule also has a sleeve-shaped fastening portion, via which the lubricantreceptacle is mounted nonrotatably on the carrier element, thus in aform fit, friction fit, or positive lock fit. The attachment of thefastening portion of the sleeve-shaped lubricant receptacle in theregion of the through-opening enables effective transport of thelubricant from the lubricant receptacle into the drilling, which runsparallel to a longitudinal axis of the crankshaft or at an angle to thelongitudinal axis, preferably the eccentric drilling in the crankshaftthat is disposed eccentrically with respect to the longitudinal axis.

In order to improve the quality of the nonrotatable connection of thecarrier element to the crankshaft, it is provided in another embodimentof the invention that the through-opening is made through asleeve-shaped prolongation of the carrier element for the connection ofthe crankshaft. The crankshaft in this case can either be held in thethrough-opening formed by the sleeve-shaped prolongation of the carrierelement or can have a recess, preferably a drilling, on the end turnedaway from the piston-cylinder-unit, in which the sleeve-shapedprolongation is held. The contact surface between crankshaft and carrierelement is greatly increased by the sleeve-shaped prolongation, which ispreferably made in one piece with the carrier element, without having toincrease the wall thickness of the carrier element at the same time. Agreater frictional force is achieved through the increased contactsurface.

In another embodiment of the invention, the carrier element togetherwith the sleeve-shaped prolongation can be produced in an especiallyinexpensive way in that the sleeve-shaped prolongation is formed fromthe carrier element by a forming operation. For example, thesleeve-shaped prolongation of the carrier element can be made as anextension of the carrier element made by a bending or deep drawingprocess.

A preferred embodiment of the refrigerant compressor according to theinvention provides that the sleeve-shaped prolongation extends towardthe side of the carrier element facing away from thepiston-cylinder-unit, a section of the crankshaft is connectednonrotatably with the through-opening, and the fastening portion of thesleeve-shaped lubricant receptacle is attached to an outer surface, withrespect to the longitudinal axis, of the sleeve-shaped prolongation. Inassembled state, a section of the crankshaft, preferably the end sectionof the crankshaft facing away from the piston-cylinder-unit, is held andconnected nonrotatably in the through-opening of the carrier element.Through this, the crankshaft is connected nonrotatably to the carrierelement, for example in a force fit or friction fit. For example, thecarrier element can be pressed or shrink-fit onto the crankshaft. Sincethe sleeve-shaped prolongation, which forms the preferably cylindricalthrough-opening, extends in the direction opposite to thepiston-cylinder-unit, thus in other words toward the bottom region ofthe compressor housing, the sleeve-shaped prolongation is particularlysuitable to hold the fastening portion of the lubricant receptacle.Because of the sleeve shape of the prolongation of the carrier element,the sleeve-shaped fastening portion of the lubricant receptacle can beattached to the sleeve-shaped prolongation of the carrier element in asimple way. The lubricant receptacle in this case is shifted outwardtoward the sleeve-shaped prolongation and is attached nonrotatably tothe sleeve-shaped prolongation of the carrier element, preferably in aforce tit, friction fit, or positive lock fit. For example, thefastening portion can be pressed or shrink-fit onto the sleeve-shapedprolongation.

To increase the surface pressure between the fastening portion of thelubricant receptacle, in particular an inner surface of the fasteningportion, and the outer surface of the sleeve-shaped prolongation of thecarrier element and thus to increase the holding force of the fasteningportion on the carrier element, in another especially preferredembodiment of the invention, it is provided that a ring-shapedsupporting element extending radially outward with respect to thelongitudinal axis surrounds at least a section of the fastening portionof the sleeve-shaped lubricant receptacle. Due to the radialcontinuation of the supporting ring, in other words due to the wallstrength of the ring-shaped supporting element, it has a high stiffness,which prevents deformation of the fastening portion and separation ofthe lubricant receptacle from the sleeve-shaped prolongation of thecarrier element. A further effect of the ring-shaped supporting elementis that the fit and holding force of the carrier element on thecrankshaft are improved through the increased stiffness, or theincreased surface pressure.

It is provided according to another preferred embodiment of therefrigerant compressor according to the invention that the fasteningportion of the sleeve-shaped lubricant receptacle is formed from thering-shaped supporting element at least in part. If the ring-shapedsupporting element and the lubricant receptacle are made in one piece,thus the supporting element is made as a cross-sectional enlargement ofthe fastening portion, the assembly of the lubricant receptacle issimplified, since the supporting element need not be separatelyassembled. At the same time, the stiffness of the fastening portion isincreased by the supporting element, so that the holding force of thelubricant receptacle on the carrier element is improved and separationof the lubricant receptacle from the carrier element is made moredifficult or prevented.

In another preferred embodiment of the invention, it is provided thatthe ring-shaped supporting element is pressed or shrink-fit onto thefastening portion of the sleeve-shaped lubricant receptacle. Theshrink-fit or pressed-on ring-shaped supporting element exerts a forcedirected radially inwardly in the direction of the longitudinal axis onan outer circumferential surface of the fastening portion of thelubricant receptacle, so that the clamping force or the resultingsurface pressure is increased. In this way, both the nonrotatable,friction- or force-fit connection of the fastening portion onto thesleeve-shaped prolongation of the carrier element and also thenonrotatable friction- or force-fit connection of the carrier element tothe crankshaft are ensured.

It is provided according to another especially preferred embodiment ofthe invention that a fastening portion of the sleeve-shaped lubricantreceptacle extends parallel to the longitudinal axis and that thesleeve-shaped lubricant receptacle has a collar section extendingradially outward with respect to the longitudinal axis, wherein thecollar section preferably bears against the carrier element. Thefastening portion of the lubricant receptacle extends parallel to thelongitudinal axis, thus in other words forms a circular cylindricalsleeve, in order to enable simple assembly. The collar section keeps thelubricant receptacle from shifting in the axial direction, thus parallelto the longitudinal axis. Preferably, the shifting is prevented in thatthe collar section contacts the carrier element. At the same time, thecollar section can also serve as a stop for the assembly of thelubricant receptacle.

An alternative embodiment of the invention provides that thesleeve-shaped prolongation extends to the side of the carrier elementfacing the piston-cylinder-unit, wherein the sleeve-shaped prolongationis connected nonrotatably to the crankshaft and the fastening portion ofthe sleeve-shaped lubricant receptacle is held nonrotatably in thethrough-opening formed by the sleeve-shaped prolongation. Thisembodiment is characterized by an especially compact construction, sincethe fastening portion of the lubricant receptacle is shifted notoutward, but rather into the through-opening, preferably is pressed intoit. In this way, the end face of the crankshaft facing away from thepiston-cylinder-unit can have a recess, into which the sleeve shapedprolongation of the carrier element is pressed, in order to make thenonrotatable connection between the carrier element and the crankshaft.

As already noted, the one-piece embodiment of sleeve-Shaped lubricantreceptacle and carrier element is a nonrotatable connection. This iswhy, in another alternative embodiment of the invention, it is providedthat the sleeve-shaped lubricant receptacle and the carrier element aremade in one piece, wherein the lubricant receptacle is formed from thecarrier element by means of a forming operation, and the end of thecrankshaft facing away from the piston-cylinder-unit is heldnonrotatably in the sleeve-shaped lubricant receptacle. Lubricantreceptacle and carrier element can in this case be made from aplate-shaped blank by means of a deep drawing process. In order to holdthe end of the crankshaft nonrotatably in the lubricant receptacle, thecarrier element can be pressed or shrink-fit onto the crankshaft. Theassembly becomes further simplified because of the one-piececonstruction, since the separate assembly of the lubricant receptacle isno longer necessary.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail by means ofembodiment examples. The drawings are examples and are intended topresent the ideas of the invention, but not to limit it in any way oreven to render it conclusively.

Here:

FIG. 1 shows a sectional view of a first embodiment of a refrigerantcompressor according to the invention;

FIG. 2 shows an enlarged detail of a bottom region of the refrigerantcompressor in FIG. 1;

FIG. 3 shows a sectional view of a bottom region of a second embodimentof the refrigerant compressor according to the invention.

WAYS OF IMPLEMENTING THE INVENTION

FIGS. 1 and 2 show a first embodiment of a refrigerant compressoraccording to the invention with a drive unit made as an external rotormotor, which is disposed in a hermetically sealable compressor housing6. The drive unit comprises a stator 3 and a rotor 4. A crankshaft 1having a longitudinal axis 2 is disposed centrally relative to thestator 3 and rotor 4, which crankshaft 1 is connected nonrotatably to acarrier element 12 of the rotor 4, for example in a form fit, frictionfit, or positive lock fit, so as to drive a piston-cylinder-unit 5 ofthe refrigerant compressor, which cyclically compresses a refrigerant.The crankshaft 1 is mounted in a bearing bushing 17 of a carrier housing18 that carries the piston-cylinder-unit 5. The stator 3, which isinwardly disposed in the radial direction with respect to thelongitudinal axis 2, is mounted on the outer side of the bearing bushing17.

The crankshaft 1 is part of a crank drive, which crank drive has acrankpin 26 eccentrically offset with respect to the longitudinal axis 2and connected directly to the crankshaft 1. The piston-cylinder-unit 5comprises a piston 25, which can be moved linearly back and forth in acylinder housing 24, a connecting rod 23 connecting the crankpin 26 tothe piston 25, a cylinder head system 27 comprising valves, and asuction muffler 28 connected to the cylinder head system 27.

In this embodiment example, the carrier housing 18 and the cylinderhousing 24 are made in one piece, more precisely as a cast part. Thecarrier housing 18 has a plurality of continuations, via which thecarrier housing 18 is mounted in the compressor housing 6 on springelements 21, which are disposed in a bottom region 7 of the compressorhousing 6. In alternative embodiments, the carrier housing 18 andcylinder housing 24 can be made in two pieces and connected to eachother by connecting means.

The rotor 4 comprises, as shown in FIG. 2, a plurality of permanentmagnets 14, which are disposed outside of the stator 3 in the radialdirection and are connected to each other in the circumferentialdirection by a shading ring 15. In order to connect the permanentmagnets 14 nonrotatably to the crankshaft 1 by force fit or frictionfit, the rotor 4 comprises the carrier element 12, which extendsradially outward from the crankshaft 1 and grips the stator 3 frombelow. The carrier element 12 is essentially made in the shape of aplate and has a raised edge section that is curved in the direction ofthe piston-cylinder-unit 5, on which the permanent magnets 14 and theshading ring 15 are attached. For connection to the crankshaft 1, thecarrier element 12 has a centrally disposed through-opening 13, so as toposition the rotor 4 coaxially with respect to the longitudinal axis 2.In these embodiment examples, the carrier element 12 has a sleeve-shapedprolongation 19 with a circular cylindrical clear cross section, whichis disposed centrally and to which the side of the carrier element 12facing away from the piston-cylinder-unit 5 extends. The through-opening13 in this case is formed by the prolongation 19. Carrier element 12 andprolongation 19 in this embodiment example are made in one piece, wherethe prolongation 19 and the edge section are formed from the carrierelement 12 by a forming process, for example a deep drawing process. Thelower end of the crankshaft 1 is in this embodiment example pressed intothe through-opening 13, so as to make the nonrotatable connection ofcarrier element 12 and crankshaft 1.

In order to lubricate the bearing points of the crankshaft 1 in thebearing bushing 17 and the piston-cylinder-unit 5 in an operating stateof the refrigerant compressor and to provide lubricant from a lubricantsump formed in the bottom region 7 of the compressor housing 6 in theoperating state, the crankshaft 1 has, at the end opposite thepiston-cylinder-unit 5, in other words at the lower end, an eccentricdrilling running at an angle to the longitudinal axis 2, in other wordsrunning essentially axially, which is eccentrically disposed withrespect to the longitudinal axis 2 in the radial direction. Lubricantthat gets into the eccentric drilling is forced to the wall of theeccentric drilling because of the centrifugal force in the rotation ofthe crankshaft 1 and, because of the increased pressure, is transportedin the direction of the piston-cylinder-unit 5. For example, theeccentric drilling can be made as a blind hole connected to the endfacing the piston-cylinder-unit 5 via a radial drilling 20 with ahelical groove 22 formed on the outer surface of the crankshaft 1 fortransport of the lubricant.

In alternative embodiments, the eccentric drilling can also be disposedrunning parallel to the longitudinal axis 2 or instead of the eccentricdrilling an axial drilling running coaxially with respect to thelongitudinal axis 2 can be provided.

In order to bring lubricant from the lubricant sump into the eccentricdrilling of the crankshaft 1 without needing a free end of thecrankshaft 1 to dip into the lubricant sump, a sleeve-shaped lubricantreceptacle 8, which is attached to the carrier element 12 and thus isnonrotatably connected to the crankshaft 1, is provided. The lower endof the crankshaft 1 here is pressed into the through-opening 13 of theprolongation 19 of the carrier element 12. In this embodiment example,the sleeve-shaped lubricant receptacle 8 and the carrier element 12 aremade in two parts, where a fastening portion 9 of the lubricantreceptacle 8 contacts the prolongation 19 of the carrier element 12.

As can easily be seen in FIG. 2, the fastening portion 9 has a circularcylindrical clear cross section, where an inner surface of the fasteningportion 9 bears against an outer surface of the sleeve-shapedprolongation 19 of the carrier element 12. In other words, the fasteningportion 9 of the sleeve-shaped lubricant receptacle 8 is pushed onto theprolongation 19. In order to make a nonrotatable connection between thelubricant receptacle 8 and carrier element 12, the fastening portion 9is as a rule pressed or shrink-fit onto the v 19 of the carrier element12 so that a force fit or friction fit connection is made.

In order to improve, on the one hand, the connection of the carrierelement 12 to the crankshaft 1 and, on the other hand, the connection ofthe fastening, portion 9 to the prolongation 19 and to increase thesurface pressure between the carrier element 12 and the fasteningportion 9 or between the fastening portion 9 and the crankshaft 1, asection of the fastening portion 9 is made as a ring-shaped supportingelement 11. In this case, it is the end of the fastening portion facingthe carrier element 12, where the ring-shaped supporting element 11extends over about 80% of the fastening portion 9 looking in the axialdirection. The ring-shaped supporting element 11 has a very large wallthickness by comparison with the rest of the lubricant receptacle 8, sothat the fastening portion 9 has high stiffness in the region of thesupporting element 11. A more reliable support of the fastening portion9 on the prolongation 19 is ensured through this.

In alternative embodiments, the ring-shaped supporting element 11 canalso be a part that is pressed or shrink-fit onto the fastening portion9 and is a separate part from the lubricant receptacle 8. In otherwords, the supporting element 11 contacts an outer circumferentialsurface of the fastening portion 9 and exerts a force on the fasteningportion 9 directed inwardly in the direction of the longitudinal axis 2.The surface pressure and the quality of the force fit or friction fitconnection between the inner surface of the through-opening 13 and thecrankshaft or between the inner surface of the fastening portion 9 andthe outer surface of the prolongation 19 is increased. The supportingelement 11 contacts a lower side of the carrier element 12 and overlapsabout 80% of the prolongation 19.

It goes without saying that the ring-shaped supporting element 11 isindeed advantageous for the attachment of the lubricant receptacle 8 onthe prolongation 19 but is not absolutely necessary. Alternatively, orin addition to the supporting element 11, the uppermost section of thelubricant receptacle 8 can also have a collar section, which extendsoutward in the radial direction at least in part.

Lubricant enters a receiving portion 10 of the lubricant receptacle 8via a lubricant inlet hole. Since the lubricant receptacle 8 has arotationally symmetric form with respect to the longitudinal axis 2 andis disposed coaxially with respect to the longitudinal axis 2, alubricant parabola or a parabola-shaped column of lubricant is formed inthe lubricant receptacle 8 by its rotation, passes into the eccentricdrilling at the lower end of the crankshaft 1, and is transportedfarther there in the direction of the first radial drilling 20.

With increasing distance between the level of liquid in the lubricantsump and the radial drilling 20, which is also called the transportheight, the transport power of the lubricant-conveying system decreases.An especially space-saving connection of the lubricant receptacle 8 tothe crankshaft 1 is achieved by the attachment of the lubricantreceptacle 8 to the sleeve-shaped prolongation 19 of the carrierelement, so that the transport height can be reduced, and with this thetransport power, thus the lubricant throughput per minute, can beincreased. The increase of the transport power can be explained in that,because of the lower transport height, the wall thickness of thelubricant parabola in the region of the radial drilling 20 is greaterand thus more lubricant reaches the helical groove 22.

It is provided in an alternative embodiment variation of the invention,which is not shown, that the lubricant receptacle 8 and carrier element12 are made in one piece and the lubricant receptacle 8 is connected tothe carrier element 12 or to the crankshaft 1 nonrotatably through this.The one-piece embodiment can be achieved, for example, by making thecarrier element 12 together with the lubricant receptacle 8 from aplate-shaped blank in a deep drawing process. In this embodiment, thelower end of the crankshaft 1 is pressed into an upper section of thelubricant receptacle 8, or the lubricant receptacle 8 is shrink-fit ontothe lower end of the crankshaft 1.

FIG. 3 shows a second embodiment variation of the invention, whichdiffers from the first embodiment in individual aspects, due to whichonly the differences will be discussed below.

While the sleeve-shaped prolongation 19 of the carrier element 12extends to the side facing away from the piston-cylinder-unit 5 in thefirst embodiment, in this embodiment example, the prolongation 19extends in the direction of the piston-cylinder-unit 5 (compare withFIG. 1). In other words, the prolongation 19 in this embodiment exampleis curved upward. The prolongation 19 is again made in one piece withthe carrier element 12 and can be made by a bending or deep drawingprocess. In the first embodiment example, the lower end of thecrankshaft 1 is disposed in the through-opening 13 made by thesleeve-shaped prolongation 19 of the carrier element 12. In the secondembodiment example, the face side of the lower end of the crankshaft 1has a central recess 29, in which recess 29 the sleeve-shapedprolongation 19 is held nonrotatably. For example, the prolongation 19can be pressed into the recess 29. The lubricant receptacle 8 in thiscase is held nonrotatably in the through-opening 13. This can also beproduced, for example, by pressing the lubricant recess 8 into thethrough-opening 13.

In addition, a lubricant driver 16, which supports the formation of thelubricant parabola and increases the transport power of the oiltransport device, can be disposed in the lubricant receptacle 8. Thus; alubricant driver 16, which has at least one or more helical surfaces,which push the lubricant outward in the direction of the inner wall ofthe lubricant receptacle 8 or are Made for pushing the lubricant in theaxial direction upward in the direction of the eccentric drilling of thecrankshaft 1, is disposed in the lubricant receptacle 8 in each of theembodiment examples described previously. It is also conceivable for theone or more surfaces of the lubricant driver 16 to be made flat.

REFERENCE NUMBER LIST

-   1 Crankshaft-   2 Longitudinal axis of crankshaft 1-   3 Stator-   4 Rotor-   5 Piston-cylinder-unit-   6 Compressor housing-   7 Bottom region of compressor housing 6-   8 Sleeve-shaped lubricant receptacle-   9 Fastening portion of lubricant receptacle 8-   10 Receiving portion of lubricant receptacle 8-   11 Ring-shaped supporting element-   12 Carrier element of rotor 4-   13 Through-opening-   14 Permanent magnet-   15 Shading ring-   16 Lubricant driver-   17 Bearing bushing-   18 Carrier housing-   19 Sleeve-shaped prolongation of carrier element 12-   20 Radial drilling-   21 Spring element-   22 Helical groove-   23 Connecting rod-   24 Cylinder housing-   25 Piston-   26 Crankpin-   27 Cylinder head arrangement-   28 Suction muffler-   29 Recess of crankshaft 1

What is claimed is:
 1. A refrigerant compressor with a, compressorhousing; an electric drive unit comprising a rotor and a stator; acrankshaft having a longitudinal axis that is nonrotatably connected tothe rotor; a piston-cylinder-unit that can be driven by the crankshaft;where the electric drive unit is made as an external rotor motor and therotor has a carrier element that extends at least partially radiallyoutward with respect to the longitudinal axis, and the carrier elementis connected nonrotatably to the crankshaft, wherein a sleeve-shapedlubricant receptacle for centrifugal transport of lubricant from alubricant sump formed in a bottom region of the compressor housing inthe direction of the piston-cylinder-unit is provided on a side of thecarrier element facing away from the piston-cylinder-unit, where thesleeve-shaped lubricant receptacle is nonrotatably connected to thecarrier element.
 2. The refrigerant compressor as in claim 1, whereinthe carrier element has a central through-opening running coaxially withrespect to the longitudinal axis, where the sleeve-shaped lubricantreceptacle is a separate component, and a fastening portion of thesleeve-shaped lubricant receptacle is attached to the carrier element inthe region of the through-opening.
 3. The refrigerant compressor as inclaim 2, wherein the through-opening is formed for the connection of thecrankshaft by a sleeve-shaped prolongation of the carrier element. 4.The refrigerant compressor as in claim 3, wherein the sleeve-shapedprolongation extends to the side of the carrier element facing away fromthe piston-cylinder-unit, a section of the crankshaft is nonrotatablyconnected to the through-opening, and the fastening portion of thesleeve-shaped lubricant receptacle is attached to an outer, with respectto the longitudinal axis, surface of the sleeve-shaped prolongation. 5.The refrigerant compressor as in claim 4, wherein a ring-shapedsupporting element that extends radially outward with respect to thelongitudinal axis surrounds at least a section of the fastening portionof the sleeve-shaped lubricant receptacle.
 6. The refrigerant compressoras in claim 5, wherein the fastening portion of the sleeve-shapedlubricant receptacle is formed at least in part by the ring-shapedsupporting element.
 7. The refrigerant compressor as in claim 5, whereinthe ring-shaped supporting element is pressed or shrink-fit onto thefastening portion of the sleeve-shaped lubricant receptacle.
 8. Therefrigerant compressor as in claim 1, wherein a fastening portion of thesleeve-shaped lubricant receptacle extends parallel to the longitudinalaxis and that the sleeve-shaped lubricant receptacle has a collarsection extending radially outward with respect to the longitudinal axisand connecting to the fastening portion.
 9. The refrigerant compressoras in claim 3, wherein the sleeve-shaped prolongation extends to theside of the carrier element that faces the piston-cylinder-unit, wherethe sleeve-shaped prolongation is connected nonrotatably to thecrankshaft, and the fastening portion of the sleeve-shaped lubricantreceptacle is held nonrotatably in the through-opening formed by thesleeve-shaped prolongation.
 10. The refrigerant compressor as in claim1, wherein the sleeve-shaped lubricant receptacle and the carrierelement are made in one piece, where the lubricant receptacle is formedfrom the carrier element by a forming operation, and the end of thecrankshaft facing away from the piston-cylinder-unit is heldnonrotatably in the sleeve-shaped lubricant receptacle.
 11. Therefrigerant compressor according to claim 1, wherein the housing ishermetically scalable.
 12. The refrigerant compressor as in claim 3,wherein the sleeve-shaped prolongation is formed from the carrierelement by means of a forming operation.
 13. The refrigerant compressoras in claim 8, wherein the collar section of the sleeve-shaped lubricantreceptacle bears against the carrier element.